While the UPOV Convention is the central international intellectual property treaty dealing with plant varieties, it has attracted comparatively little attention. To the extent that there has been discussion of the UPOV Convention, it has been characterised by the fact that most scholarship in this area has focused on specific national or regional implementation of the UPOV Convention. Furthermore, a number of assumptions are commonly made in the scholarship on the UPOV Convention and UPOV-based schemes including that UPOV is sui generis; that it is out-dated and obsolete; and that the UPOV Convention has increasingly come to resemble patent protection. To contribute to, and move beyond, this scholarship this thesis has two interrelated aims. These are: (1) to explore historically some of the key ideas, aspects and concepts that underpin and inform the UPOV Convention; and (2) to critically engage with the assumptions commonly made about the UPOV Convention. While the thesis does not engage directly with normative or doctrinal inquiries, this kind of historical analysis is important as the UPOV Union and the UPOV Convention are at an important juncture, with unresolved questions over the effectiveness of the Convention, as well as over the relevance of, and need for, a separate international treaty on plant varieties. By highlighting the changes that have occurred over the past fifty years, as well as the actors involved in these changes, the thesis uncovers the relational, interactive and juridical nature of the UPOV Convention; suggesting a more mobile and mutable law than has previously been discussed. As a consequence those involved in UPOV — including the UPOV Union, member states, plant breeding organisations, non-government organisations, other industry bodies and academics — must clearly and explicitly acknowledge the relational, interactive and juridical nature of the UPOV Convention. Indeed, it can no longer be assumed that the UPOV Convention is simply sui generis, out-dated and patent-like.